Energy From Thorium Discussion Forum

It is currently Oct 23, 2017 3:32 pm

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 6 posts ] 
Author Message
PostPosted: Aug 19, 2014 12:27 pm 
Offline
User avatar

Joined: Nov 30, 2006 3:30 pm
Posts: 3306
Location: Alabama
In Vaclav Dostal's work on SCO2, in the gas cooler CO2 is cooled from 70C to 32C at a pressure of 77 bar. Assuming that one was cooling the CO2 with water at ambient pressure, and that one assumed a delta-T across the gas cooler of 5C, then the water would heat from 27C to 65C.

For a 600 MWt input to the power conversion system, the mass flow rate through the gas cooler is 1874 kg/s, and the required mass flow rate of water to do the cooling is 2050 kg/s.

Does anyone on here have experience with wet cooling towers and could offer some insight into how best to cool water from 65C to 27C at a mass flow rate of 2050 kg/s? What would the rate of makeup water be to such a system? Which evaporative cooling approach might be best?

Update: found this excellent online calculator:

GEA COOLING TOWER CALCULATOR

and got this result:

Attachment:
H2O-65C-27C-CoolingTower.pdf [298.12 KiB]
Downloaded 76 times


Top
 Profile  
 
PostPosted: Aug 19, 2014 1:09 pm 
Offline

Joined: Jul 14, 2008 3:12 pm
Posts: 5058
What kind of cooling system is this? Are you pumping plant service water directly and so have to deal with dirty water in the gas cooler? Or is it clean water in the gas cooler but needing another closed heat exchange to the service water evaporation cooling? If the former, have you considered integrating the gas cooler with the cooling tower? If the latter, have you considered a PCHE gas cooler? They can get to under 2C approach temperature. They are ideally suited to this sort of thing.

Where are you thinking to build this thing? It is going to be pretty critical on the wet bulb temperature if you really need 27C as a max. If its in a humid hot climate this can become a real problem. Especially because it is attractive to cool the CO2 to below 32C to get efficiency improvement.

GEA are a great bunch. Would be good to just hire them to work out the details of your system, they know what they're doing and can work in a variety of cooling technology markets.


Top
 Profile  
 
PostPosted: Aug 19, 2014 1:47 pm 
Offline
User avatar

Joined: Nov 30, 2006 3:30 pm
Posts: 3306
Location: Alabama
Cyril R wrote:
Where are you thinking to build this thing? It is going to be pretty critical on the wet bulb temperature if you really need 27C as a max. If its in a humid hot climate this can become a real problem. Especially because it is attractive to cool the CO2 to below 32C to get efficiency improvement.


Assume Alabama---a place well known for high temperatures and high humidity.

Cyril R wrote:
GEA are a great bunch. Would be good to just hire them to work out the details of your system, they know what they're doing and can work in a variety of cooling technology markets.


Do you have any points-of-contact there?


Top
 Profile  
 
PostPosted: Aug 19, 2014 2:34 pm 
Offline

Joined: Jul 14, 2008 3:12 pm
Posts: 5058
Quote:
Assume Alabama---a place well known for high temperatures and high humidity.


Well, at the limit, a 100% humidity means the dry bulb is the wet bulb temperature (no evaporative cooling). That means you can't have ambient temperatures of 27C or higher if you want to maintain the temperature drops. Clearly even with 26C and high humidity you will have a high surface area and fan power need. But that's probably not a big deal because the cooler is relatively cheap. The optimum probably lies in quite aggressive pinch points, with almost no temperature drop across streams. That means big fans, big coolers, and big pumps.

Quote:
Do you have any points-of-contact there?


Not for GEA USA. I think your best bet is to send an email to the cooling tower division of the GEA US, "GEA Cooling Tower Solutions". They have an office in Florida so they know about humidity!

coolingtowers.hx.us@gea.com

It beats guesswork on a forum.

Ideally you can use one of the standard products, but the modular cooling towers are probably too tiny for this application (you'd need a great many).


Top
 Profile  
 
PostPosted: Aug 25, 2014 4:09 am 
Offline

Joined: Feb 05, 2013 5:24 am
Posts: 108
Cyril R wrote:
What kind of cooling system is this? Are you pumping plant service water directly and so have to deal with dirty water in the gas cooler? Or is it clean water in the gas cooler but needing another closed heat exchange to the service water evaporation cooling? If the former, have you considered integrating the gas cooler with the cooling tower? If the latter, have you considered a PCHE gas cooler? They can get to under 2C approach temperature. They are ideally suited to this sort of thing.




I don't think the PCHE can take the fatigue of the delta T's and transients, but there are other compact heat exchangers, like metal mesh and wavy fin, that are under development.


Top
 Profile  
 
PostPosted: Aug 25, 2014 8:03 am 
Offline

Joined: Jul 14, 2008 3:12 pm
Posts: 5058
Ed P wrote:
Cyril R wrote:
What kind of cooling system is this? Are you pumping plant service water directly and so have to deal with dirty water in the gas cooler? Or is it clean water in the gas cooler but needing another closed heat exchange to the service water evaporation cooling? If the former, have you considered integrating the gas cooler with the cooling tower? If the latter, have you considered a PCHE gas cooler? They can get to under 2C approach temperature. They are ideally suited to this sort of thing.




I don't think the PCHE can take the fatigue of the delta T's and transients, but there are other compact heat exchangers, like metal mesh and wavy fin, that are under development.


I hear this stuff a lot, mostly from academics who refer to entirely theoretical models of stress and fatigue. There appears to be no experimental support for these claims as various PCHEs are in operation in high dT and cyclic operation with no reported issues. Do you have any case studies where PCHEs have failed in high dT and/or cyclic/transient environments? My interest in this area is more than academical.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 6 posts ] 

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group